1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // SH7760 ("camelot") DMABRG audio DMA unit support
4 //
5 // Copyright (C) 2007 Manuel Lauss <mano@roarinelk.homelinux.net>
6 //
7 // The SH7760 DMABRG provides 4 dma channels (2x rec, 2x play), which
8 // trigger an interrupt when one half of the programmed transfer size
9 // has been xmitted.
10 //
11 // FIXME: little-endian only for now
12
13 #include <linux/module.h>
14 #include <linux/gfp.h>
15 #include <linux/init.h>
16 #include <linux/platform_device.h>
17 #include <linux/dma-mapping.h>
18 #include <sound/core.h>
19 #include <sound/pcm.h>
20 #include <sound/pcm_params.h>
21 #include <sound/soc.h>
22 #include <asm/dmabrg.h>
23
24
25 /* registers and bits */
26 #define BRGATXSAR 0x00
27 #define BRGARXDAR 0x04
28 #define BRGATXTCR 0x08
29 #define BRGARXTCR 0x0C
30 #define BRGACR 0x10
31 #define BRGATXTCNT 0x14
32 #define BRGARXTCNT 0x18
33
34 #define ACR_RAR (1 << 18)
35 #define ACR_RDS (1 << 17)
36 #define ACR_RDE (1 << 16)
37 #define ACR_TAR (1 << 2)
38 #define ACR_TDS (1 << 1)
39 #define ACR_TDE (1 << 0)
40
41 /* receiver/transmitter data alignment */
42 #define ACR_RAM_NONE (0 << 24)
43 #define ACR_RAM_4BYTE (1 << 24)
44 #define ACR_RAM_2WORD (2 << 24)
45 #define ACR_TAM_NONE (0 << 8)
46 #define ACR_TAM_4BYTE (1 << 8)
47 #define ACR_TAM_2WORD (2 << 8)
48
49
50 struct camelot_pcm {
51 unsigned long mmio; /* DMABRG audio channel control reg MMIO */
52 unsigned int txid; /* ID of first DMABRG IRQ for this unit */
53
54 struct snd_pcm_substream *tx_ss;
55 unsigned long tx_period_size;
56 unsigned int tx_period;
57
58 struct snd_pcm_substream *rx_ss;
59 unsigned long rx_period_size;
60 unsigned int rx_period;
61
62 } cam_pcm_data[2] = {
63 {
64 .mmio = 0xFE3C0040,
65 .txid = DMABRGIRQ_A0TXF,
66 },
67 {
68 .mmio = 0xFE3C0060,
69 .txid = DMABRGIRQ_A1TXF,
70 },
71 };
72
73 #define BRGREG(x) (*(unsigned long *)(cam->mmio + (x)))
74
75 /*
76 * set a minimum of 16kb per period, to avoid interrupt-"storm" and
77 * resulting skipping. In general, the bigger the minimum size, the
78 * better for overall system performance. (The SH7760 is a puny CPU
79 * with a slow SDRAM interface and poor internal bus bandwidth,
80 * *especially* when the LCDC is active). The minimum for the DMAC
81 * is 8 bytes; 16kbytes are enough to get skip-free playback of a
82 * 44kHz/16bit/stereo MP3 on a lightly loaded system, and maintain
83 * reasonable responsiveness in MPlayer.
84 */
85 #define DMABRG_PERIOD_MIN 16 * 1024
86 #define DMABRG_PERIOD_MAX 0x03fffffc
87 #define DMABRG_PREALLOC_BUFFER 32 * 1024
88 #define DMABRG_PREALLOC_BUFFER_MAX 32 * 1024
89
90 static const struct snd_pcm_hardware camelot_pcm_hardware = {
91 .info = (SNDRV_PCM_INFO_MMAP |
92 SNDRV_PCM_INFO_INTERLEAVED |
93 SNDRV_PCM_INFO_BLOCK_TRANSFER |
94 SNDRV_PCM_INFO_MMAP_VALID |
95 SNDRV_PCM_INFO_BATCH),
96 .buffer_bytes_max = DMABRG_PERIOD_MAX,
97 .period_bytes_min = DMABRG_PERIOD_MIN,
98 .period_bytes_max = DMABRG_PERIOD_MAX / 2,
99 .periods_min = 2,
100 .periods_max = 2,
101 .fifo_size = 128,
102 };
103
104 static void camelot_txdma(void *data)
105 {
106 struct camelot_pcm *cam = data;
107 cam->tx_period ^= 1;
108 snd_pcm_period_elapsed(cam->tx_ss);
109 }
110
111 static void camelot_rxdma(void *data)
112 {
113 struct camelot_pcm *cam = data;
114 cam->rx_period ^= 1;
115 snd_pcm_period_elapsed(cam->rx_ss);
116 }
117
118 static int camelot_pcm_open(struct snd_soc_component *component,
119 struct snd_pcm_substream *substream)
120 {
121 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
122 struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
123 int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
124 int ret, dmairq;
125
126 snd_soc_set_runtime_hwparams(substream, &camelot_pcm_hardware);
127
128 /* DMABRG buffer half/full events */
129 dmairq = (recv) ? cam->txid + 2 : cam->txid;
130 if (recv) {
131 cam->rx_ss = substream;
132 ret = dmabrg_request_irq(dmairq, camelot_rxdma, cam);
133 if (unlikely(ret)) {
134 pr_debug("audio unit %d irqs already taken!\n",
135 snd_soc_rtd_to_cpu(rtd, 0)->id);
136 return -EBUSY;
137 }
138 (void)dmabrg_request_irq(dmairq + 1,camelot_rxdma, cam);
139 } else {
140 cam->tx_ss = substream;
141 ret = dmabrg_request_irq(dmairq, camelot_txdma, cam);
142 if (unlikely(ret)) {
143 pr_debug("audio unit %d irqs already taken!\n",
144 snd_soc_rtd_to_cpu(rtd, 0)->id);
145 return -EBUSY;
146 }
147 (void)dmabrg_request_irq(dmairq + 1, camelot_txdma, cam);
148 }
149 return 0;
150 }
151
152 static int camelot_pcm_close(struct snd_soc_component *component,
153 struct snd_pcm_substream *substream)
154 {
155 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
156 struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
157 int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
158 int dmairq;
159
160 dmairq = (recv) ? cam->txid + 2 : cam->txid;
161
162 if (recv)
163 cam->rx_ss = NULL;
164 else
165 cam->tx_ss = NULL;
166
167 dmabrg_free_irq(dmairq + 1);
168 dmabrg_free_irq(dmairq);
169
170 return 0;
171 }
172
173 static int camelot_hw_params(struct snd_soc_component *component,
174 struct snd_pcm_substream *substream,
175 struct snd_pcm_hw_params *hw_params)
176 {
177 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
178 struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
179 int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
180
181 if (recv) {
182 cam->rx_period_size = params_period_bytes(hw_params);
183 cam->rx_period = 0;
184 } else {
185 cam->tx_period_size = params_period_bytes(hw_params);
186 cam->tx_period = 0;
187 }
188 return 0;
189 }
190
191 static int camelot_prepare(struct snd_soc_component *component,
192 struct snd_pcm_substream *substream)
193 {
194 struct snd_pcm_runtime *runtime = substream->runtime;
195 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
196 struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
197
198 pr_debug("PCM data: addr %pad len %zu\n", &runtime->dma_addr,
199 runtime->dma_bytes);
200
201 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
202 BRGREG(BRGATXSAR) = (unsigned long)runtime->dma_area;
203 BRGREG(BRGATXTCR) = runtime->dma_bytes;
204 } else {
205 BRGREG(BRGARXDAR) = (unsigned long)runtime->dma_area;
206 BRGREG(BRGARXTCR) = runtime->dma_bytes;
207 }
208
209 return 0;
210 }
211
212 static inline void dmabrg_play_dma_start(struct camelot_pcm *cam)
213 {
214 unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
215 /* start DMABRG engine: XFER start, auto-addr-reload */
216 BRGREG(BRGACR) = acr | ACR_TDE | ACR_TAR | ACR_TAM_2WORD;
217 }
218
219 static inline void dmabrg_play_dma_stop(struct camelot_pcm *cam)
220 {
221 unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
222 /* forcibly terminate data transmission */
223 BRGREG(BRGACR) = acr | ACR_TDS;
224 }
225
226 static inline void dmabrg_rec_dma_start(struct camelot_pcm *cam)
227 {
228 unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
229 /* start DMABRG engine: recv start, auto-reload */
230 BRGREG(BRGACR) = acr | ACR_RDE | ACR_RAR | ACR_RAM_2WORD;
231 }
232
233 static inline void dmabrg_rec_dma_stop(struct camelot_pcm *cam)
234 {
235 unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
236 /* forcibly terminate data receiver */
237 BRGREG(BRGACR) = acr | ACR_RDS;
238 }
239
240 static int camelot_trigger(struct snd_soc_component *component,
241 struct snd_pcm_substream *substream, int cmd)
242 {
243 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
244 struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
245 int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
246
247 switch (cmd) {
248 case SNDRV_PCM_TRIGGER_START:
249 if (recv)
250 dmabrg_rec_dma_start(cam);
251 else
252 dmabrg_play_dma_start(cam);
253 break;
254 case SNDRV_PCM_TRIGGER_STOP:
255 if (recv)
256 dmabrg_rec_dma_stop(cam);
257 else
258 dmabrg_play_dma_stop(cam);
259 break;
260 default:
261 return -EINVAL;
262 }
263
264 return 0;
265 }
266
267 static snd_pcm_uframes_t camelot_pos(struct snd_soc_component *component,
268 struct snd_pcm_substream *substream)
269 {
270 struct snd_pcm_runtime *runtime = substream->runtime;
271 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
272 struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
273 int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
274 unsigned long pos;
275
276 /* cannot use the DMABRG pointer register: under load, by the
277 * time ALSA comes around to read the register, it is already
278 * far ahead (or worse, already done with the fragment) of the
279 * position at the time the IRQ was triggered, which results in
280 * fast-playback sound in my test application (ScummVM)
281 */
282 if (recv)
283 pos = cam->rx_period ? cam->rx_period_size : 0;
284 else
285 pos = cam->tx_period ? cam->tx_period_size : 0;
286
287 return bytes_to_frames(runtime, pos);
288 }
289
290 static int camelot_pcm_new(struct snd_soc_component *component,
291 struct snd_soc_pcm_runtime *rtd)
292 {
293 struct snd_pcm *pcm = rtd->pcm;
294
295 /* dont use SNDRV_DMA_TYPE_DEV, since it will oops the SH kernel
296 * in MMAP mode (i.e. aplay -M)
297 */
298 snd_pcm_set_managed_buffer_all(pcm,
299 SNDRV_DMA_TYPE_CONTINUOUS,
300 NULL,
301 DMABRG_PREALLOC_BUFFER, DMABRG_PREALLOC_BUFFER_MAX);
302
303 return 0;
304 }
305
306 static const struct snd_soc_component_driver sh7760_soc_component = {
307 .open = camelot_pcm_open,
308 .close = camelot_pcm_close,
309 .hw_params = camelot_hw_params,
310 .prepare = camelot_prepare,
311 .trigger = camelot_trigger,
312 .pointer = camelot_pos,
313 .pcm_construct = camelot_pcm_new,
314 };
315
316 static int sh7760_soc_platform_probe(struct platform_device *pdev)
317 {
318 return devm_snd_soc_register_component(&pdev->dev, &sh7760_soc_component,
319 NULL, 0);
320 }
321
322 static struct platform_driver sh7760_pcm_driver = {
323 .driver = {
324 .name = "sh7760-pcm-audio",
325 },
326
327 .probe = sh7760_soc_platform_probe,
328 };
329
330 module_platform_driver(sh7760_pcm_driver);
331
332 MODULE_LICENSE("GPL v2");
333 MODULE_DESCRIPTION("SH7760 Audio DMA (DMABRG) driver");
334 MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");
335
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